A voltage regulator uses a reference current source and a supply voltage (battery) to deliver a regulated output voltage, that is to say one which is independent of the variations in the supply voltage.
For reasons of stability, low dropout voltage regulators may be connected to a decoupling capacitor, arranged in parallel with a load to which the regulator delivers a load current via a power transistor fed back to an operational amplifier. The maximum value of the load current depends on the dimensions of the power transistor. With a view to optimization, it is necessary to match these dimensions to the load current. Since the power transistor has a large stray capacitance, the output stage of the operational amplifier should furthermore be matched to the power transistor, and therefore to the maximum load current. Any modification in the value of the maximum load current thus entails changing the power transistor and matching the regulator core comprising the operational amplifier. This technique represents a great time constraint in terms of planning the integrated circuit.
According what is needed is a method and system to over come the problems and constraints encountered in the prior art and to provide a low dropout voltage regulator which modulates the load current.